Tunable filters developed at CRI, based on electrically-tuned liquid crystal waveplates, provide fluorescence microscopists with fast, continuously tunable, automated selection of emission wavelength without vibration, image shift, or degradation of image quality. Spectroscopic analysis of fluorescence emission, as well as multiple label and ratio imaging experiments, can be performed rapidly and interactively. However, present liquid crystal tunable filters (LCTF's) offer rather low throughput (10 to 25%) limiting their usefulness in photon-limited fluorescence applications. Our aim in this work is to develop a new type of liquid crystal tunable filter, with transmission of 70% or more. Phase I results indicate that the device is feasible. During Phase II, prototypes will be built and field tested. Work will include the development of a convenient optical / mechanical interface and interactive software. PROPOSED COMMERCIAL APPLICATION: This device would make possible faster, automated multi-spectral measurements of fluorescence emission in living cell microscopy without vibration. The first market for these devices will be research labs involved in fluorescence experiments. Eventually, as clinical techniques-develop using the capabilities of this device, we expect it to find applications in automated clinical diagnostic testing.